hyperlane-monorepo/solidity/core/interfaces/IInbox.sol

// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity >=0.6.11;

import {IMailbox} from "./IMailbox.sol";

interface IInbox is IMailbox {
    function remoteDomain() external returns (uint32);

    function process(
        bytes32 _root,
        uint256 _index,
        bytes calldata _message,
        bytes32[32] calldata _proof,
        uint256 _leafIndex
    ) external;
}